Weight gain due to vitamin D deficiency: the most important questions and answers

Gewichtszunahme durch Vitamin D Mangel: Die wichtigsten Fragen und Antworten

Did you know that there is a relationship between vitamin D deficiency and weight gain? In this article we will show you in a detailed but understandable way how the metabolism works and how you can support your body in losing weight. We will explain to you the biological processes by which hormones are produced and which control the storage of fat.

Valuable tips await you on how to determine if a vitamin D deficiency is the cause of your weight gain and where to get enough vitamin D. We present the background, advantages and disadvantages of supplementing with vitamin D. Finally, we give you alternative solutions if you do not want to take any supplements.

the essentials in brief

  • Vitamin D regulates the release of the hormones leptin and adiponectin. They have an influence on the fat storage in the human body, on your feeling of hunger and the effectiveness of insulin.
  • To correct the vitamin D deficiency, you can take it in the diet and dietary supplements. With the help of sunshine, your body can make its own vitamin D from cholesterol in the skin.
  • There are alternative ways to lose weight, but the easiest solution is to directly address the cause of the weight gain, i.e. the vitamin D deficiency, instead of fighting your metabolism.

Background: What you should know about vitamin D deficiency and weight gain

Body weight and its increase and decrease is a complex issue. Weight gain can have various causes. One of them is vitamin D deficiency. In the human metabolism, a huge number of biological processes are carried out, which are interdependent.

A vitamin D deficiency does not affect weight directly, but controls the release of other hormones, which as an intermediate stage lead to fat storage and energy consumption. In this article, we have thoroughly researched the biochemistry of the human body and explain everything behind your weight gain and what you need to know about the cause.

How Exactly Does Vitamin D Deficiency Cause Weight Gain?

Overweight people usually suffer from a vitamin D deficiency, which they should definitely compensate in order to prevent a whole range of diseases. In the case of a vitamin D deficiency, the hormone leptin is released less. Leptin lets your body know when it has enough fat (1). Vitamin D itself also regulates the storage of fat in your muscles.

Another hormone that is important in the process of storing fat is called adiponectin. It regulates the effectiveness of insulin (2). So if you have too little adiponectin, your insulin is less effective and your risk of developing diabetes increases (3).

Adiponectin in cooperation with leptin also influences how hungry you feel (4). The more adiponectin your body has, the faster you will feel full. The adiponectin level in the blood is directly dependent on the vitamin D values.

How do I know if my weight gain is due to a vitamin D deficiency?

Weight gain is a very complex issue and there are a number of factors that can lead to it. If your weight gain is caused by a vitamin D deficiency, you will also notice other symptoms of a vitamin D deficiency.

The easiest way to determine if you are deficient in vitamin D is with a blood test (5). If there is a suspicion that you might be suffering from a vitamin D deficiency, the determination of vitamin D levels will be paid for by your health insurance company. If you are just curious and still want to do such a test, you should expect a price of around 20 euros.

A healthy person has over 30 nanograms of vitamin D in every milliliter of blood. Less than 20 nanograms is already considered a deficiency (6). If this is your case, your doctor will recommend a vitamin D supplement that contains 25 µg of vitamin D. Such tablets or drops should be taken once a day.

If you don't want to go to the doctor, you can also use so-called self-tests from the pharmacy. After you send a few drops of your blood to a lab, you'll receive the result by email. These tests are not 100% reliable and it is possible that the recommended dose of vitamin D is too high compared to a doctor's measurement.

You can roughly diagnose a vitamin D deficiency without doing a blood test. If you suffer from a long-term deficiency, you will experience some of the following symptoms:

  • Bone pain: Vitamin D is responsible for calcium absorption in the body and thus for bone formation. When your body doesn't have enough vitamin D, bone density decreases and osteomalacia (softening of the bones) develops, which can lead to pain and fractures (7).
  • Mood swings and depression: The release of serotonin, a neurotransmitter responsible for psychological well-being, is also dependent on the vitamin D level in the blood (8). Low vitamin D levels can lead to bad mood and depression.
  • Respiratory infections: Vitamin D also boosts the immune system by stimulating T-lymphocytes (white blood cells involved in immune defense) to divide after contact with pathogens (9). If your immune system becomes unstable due to a vitamin D deficiency and your immune cells are weakened, respiratory infections can occur more easily.

So if you notice one or more of the above symptoms over the long term, you should address a potential vitamin D deficiency with your doctor. This may also be the cause of your weight gain, and once the balance is restored, the weight should move in the desired direction.

When is it important to control weight gain?

You suddenly gained weight, but you don't know exactly whether and what you should do about it? A slight increase in weight is often normal and does not pose a health risk. Often people want to lose weight to become more physically attractive.

If you find that you have suddenly gained a lot of pounds without changing your diet and eating significantly more, you should definitely ask about the possible reasons. If a hormonal disorder or other imbalance is involved, it can also lead to other health problems (10). In such a case, you should definitely remove the cause of your weight gain.


When you should control weight gain depends on your motivation. Sometimes it's visual, but when it comes to health, it's important to look into the cause. (Image source: pixabay.com / Vidmir Raic)

You should never embark on a drastic diet to lose weight that fights your body's physiological processes. If being overweight bothers you, whether for aesthetic or health reasons, always check with a qualified doctor.

How can I lose weight with sunshine?

When your body has enough active vitamin D3, it can carry out all of the above biological processes. That is, thanks to the sun, provitamin D and vitamin D3 are produced, and vitamin D3 is used to produce the hormones leptin and adiponectin, which regulate the storage of fat in the body, the effectiveness of insulin, and the feeling of hunger (12). Then it will be much easier for your body to lose excess weight.

In order to get enough sun to make vitamin D while preventing the risk of skin cancer, you should be careful about your exposure to the sun. In winter, the skin doesn't get much sun. Therefore, it is ideal to form vitamin D before winter and to store it for the time. The best time to do this is between March and October from 10am to 3pm for 15 to 30 minutes. The freer the skin is, the better. Without sunscreen, your skin absorbs the sunshine much better.

To save yourself from cancer, you should definitely avoid sunburn. It is much more effective to go into the sun three times a week than to lie on the beach for two weeks once a year. Also, people with darker skin types need more sun to produce the same amount of vitamin D, while those with lighter and more sensitive skin should be careful.

The pigment melanin, which causes the coloring of the skin, hair and eyes, serves as protection against UV radiation from the sun.

When and for whom is vitamin D supplementation useful?

There is a huge selection of preparations, dietary supplements and even medicines available on the market today. Before deciding which ones are best, you should determine if and what you need them for in the first place.

It's only when you find that you can't get enough vitamin D from your diet and from synthesizing your skin with sunshine that you should supplement with vitamin D (13). Dietary supplements help you to cover your daily vitamin D requirement without having to guess how much certain foods contain.

Vitamin D capsule

Supplements with vitamin D in the form of tablets, capsules or drops can make it easier for you to take it. But always be clear about whether you really need it and pay attention to the right dosage. (Image source: unsplash.com / Michele Blackwell)

How Much Vitamin D Do I Need to Prevent Weight Gain?

If you are vitamin D deficient, and especially if you decide to supplement your diet with vitamin D, you should do your research on recommended dosages. According to the Federal Institute for Risk Assessment, the daily limit is 20 µg of vitamin D that you should take in dietary supplements.

Higher dosages are considered medications and must be prescribed by your doctor. Before taking any vitamin D supplement, it may be worth discussing your needs with a qualified healthcare practitioner.

daily dose interpretation
20 µg Recommended daily dose
50mcg Overdose adds up over time
100mcg Serious health risk

In any case, your body does not need any preparations with a dosage of more than 50 µg. If you occasionally take such dietary supplements, your health is not directly endangered. However, if you regularly take high-dose supplements, there is a health risk (14.15">. You should never take more than 100 µg a day. Possible symptoms of a vitamin D overdose are:

  • Headache, vomiting and constipation
  • nausea and loss of appetite
  • Kidney calcification, kidney stones and even kidney failure

Because vitamin D can be stored in the body, even a slight but regular overdose can cause damage to health over time (16).

What alternatives are there to vitamin D supplementation?

Now you have learned a lot about the relationship between vitamin D deficiency and weight gain and got to know the complex hormonal processes in your body. In the following section we will show you which alternatives are available to you if you want to fight obesity without having to take supplements. While body weight can be managed in a variety of ways, you should understand exactly what is causing your weight gain and address that cause.

Optimal health through a balanced diet and enough exercise gives your metabolism the chance to carry out all important biological processes and thus also to maintain an optimal weight. Sleep and stress also play a critical role in weight gain and loss. Last but not least, the sunshine can also help you improve your vitamin D levels without taking any supplements. Next, we give you detailed information on each individual influencer.

Eating right and drinking enough

To achieve weight loss, you should get fewer calories from food than your body uses. The energy required is then taken in the form of stored fat. In addition to the calorie requirement and consumption, the quality of the food is also important. A balanced diet guarantees that your body has all the nutrients it needs to carry out biological processes and avoid deficiencies and disorders.

To save yourself from vitamin D supplementation, get enough vitamin D in your diet (17). Fat-free fish meat contains a particularly large amount of vitamin D. A 100 g portion of herring gives you enough for a whole day. If you eat vegan, you can eat a lot of avocados and mushrooms. There is also some vitamin D in eggs, liver and offal.

Groceries Vitamin D per 100g
herring 25mcg
Salmon 16mcg
avocados 6 µg
eggs (18) 2.9 µg
mushrooms 1.9 µg

If you use enough pure water instead of e.g. B. drinking sweet juices, less insulin is shaken out of the body and you burn the excess fat faster (19). Don't drink too much water, though, as it can damage your kidneys. Depending on your body weight, lifestyle and temperature, your need for water will be higher or lower. According to the German Society for Nutrition, a guide value of 1.5 liters per day is recommended. You should not drink more than 3 liters in the long term.


If your calorie expenditure is the same as your calorie intake, the weight stays the same. When you gain weight, it means you're taking in more energy than you're burning. So if you want to lose weight, your calorie needs must be higher than the amount of energy contained in the food you eat.

Of course, your body also burns a lot of calories when you're not moving too much. Your basal metabolic rate is how much energy you use to maintain vital functions. This includes processes such as brain functions, digestion, breathing, etc. The basal metabolic rate is very different for each person and depends on age, gender, weight and body composition. The power turnover indicates how many calories you need for your everyday activities, such as your job and sports.

Finding an exercise you enjoy is important to maintaining a long-term healthy lifestyle. Then all you have to do is calculate how much energy you get from your diet and how much you use in everyday life and during sports. In order to burn the stored fat in your body and lose weight, you need to burn more calories than you take in.

sleep and stress reduction

Healthy sleep is important for many reasons. With enough sleep, your body can carry out all its metabolisms calmly during the night. While you sleep, the stress hormone cortisol, which is responsible for fat storage, is broken down (20). If the body doesn't get enough sleep, it can't get rid of the excess cortisol and more fat is stored. For the same reason, you should avoid unnecessary stress (21).

Woman is late at the laptop in bed

When you work late hours, don't get enough sleep, and stress yourself out too much, your body can't break down the hormone cortisol and keep your metabolism running smoothly. (Image source: unsplash.com / Victoria Heath)

In addition, the hormone leptin, which is responsible for your feeling of satiety, is released during sleep. If you don't get enough sleep, your body uses muscle instead of fat for quick energy and sheds your muscle mass.


As already mentioned, a short stay in the sun can do a lot of health things for you. If you don't want to take vitamin D supplements, you can also combat vitamin D deficiency with the help of the sun. When sunshine touches your skin, provitamin D is made from cholesterol and later stored in the liver as vitamin D (22).

Thanks to the sun, your body can produce vitamin D itself without taking it externally. With enough vitamin D, all hormonal processes can be carried out calmly and you will lose weight much more easily, because there are no disorders and imbalances in the body (23.24">.


You now understand how complex the metabolism in the human body is and how body weight is influenced by various factors. Vitamin D plays an important role in the fat storage process. It regulates the release of leptin and adiponectin. These two hormones control the storage of fat and your feeling of hunger. Adiponectin also affects the effectiveness of insulin.

You have also learned how to determine and improve your vitamin D levels. You can get vitamin D externally in two ways: in foods and dietary supplements. In addition, your body can make its own vitamin D when the skin comes into contact with the sunshine. Even if you don't want to take supplements, there are alternative solutions to vitamin D deficiency-related weight gain.


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